Abstract: A radio frequency power amplifier module for a dual-band type mobile communication apparatus that can transmit and receive the first frequency f1 and the second frequency f2 (f2=2×f1) is structured as explained below.

Abstract: In a mobile telephone apparatus corresponding to dual-band provided with an RF power module to operate in two kinds of different frequencies, a common harmonics control circuit is provided to the output circuit of such RF power module to realize higher efficiency in view of controlling respective harmonics power for both band frequencies. Moreover, a means for selectively setting the bias is also provided so that the maximum efficiency can be attained depending on the output power required with respective communication systems with the bias control signal output from the CPU of the control unit interlocking with selection of frequency of the mobile telephone apparatus body. In addition, a switching element is also provided to such harmonics control circuit to enable the harmonics control without giving any influence on the radio frequency signal of each communication system.

Abstract: A radio frequency power amplifier module for a dual-band type mobile communication apparatus that can transmit and receive the first frequency f1 and the second frequency f2 (f2=2×f1) is structured as explained below. This radio frequency power amplifier module for dual-band type mobile communication apparatus is comprised of a drive stage amplifier having the gain peaks at f1 and f2 with a matching circuit and a radio frequency power output circuit including a radio frequency power output transistor.

Abstract: In a mobile telephone apparatus corresponding to dual-band provided with an RF power module to operate in two kinds of different frequencies, a common harmonics control circuit is provided to the output circuit of such RF power module to realize higher efficiency in view of controlling respective harmonics power for both band frequencies. Moreover, a means for selectively setting the bias is also provided so that the maximum efficiency can be attained depending on the output power required with respective communication systems with the bias control signal output from the CPU of the control unit interlocking with selection of frequency of the mobile telephone apparatus body.

Abstract: An electrochemical gas sensor includes, as disposed on an insulating substrate, a plurality of electrodes for individually sensing a standard gas present in a surrounding atmosphere at a fixed concentration and a target gas present in the surrounding atmosphere, and a signal processing circuit for determining sensor life on the basis of sensed outputs of the standard gas. Constant detection of the sensitivity characteristics of the gas sensor is thereby attained for self-examination of the life thereof.

Abstract: An electrochemical gas sensor comprises an insulating substrate, active and counter electrodes disposed on a surface of the insulating substrate mutually spaced to have respectively reactive portions, a reference electrode spaced from the active and counter electrodes and having a reactive portion, and a solid electrolyte layer formed to cover the reactive portions of the active, counter and reference electrodes, whereby the sensitivity to gases of the active electrode is improved and stabilized.